Blood is always red, never blue.

[ollie1]

i cut my shin and instanly the blood ran down my leg and was blue and then turned red

[clarisse]

I have never heard of blood being blue. My biology teacher always said that blood color is red, although it's true that veins are blue, but then again veins are not the blood itself.

[ReginaM]

It is quite interesting to look for the right answer about whether blood can be blue or not on the Internet. It seems everyone has the 'facts' to back there claim up. Technically you could also say that blood is clear if it has just white blood cells and no red blood cells.

[biohazard]

I don't understand how this topic can keep going and going. Quite clearly, if you take a venous blood sample into an evacuated tube you can see the blood is dark red. If you use the same method to draw an arterial blood sample the blood is bright red. And yes, the blood is colourless if you remove erythrocytes, but I doubt we can call it blood anymore then.

Blood is blue if you have haemocyanin instead of haemoglobin, but that require you to be a horseshoe crab or similar, which utilizes copper instead of iron to carry oxygen. And I do not think we are talking about marine arthropods here...

[claireoreo]

Why do we lose 21 grams when we die?

because overtime, the water in our body evaporates.

[animartco]

So why do our lips turn blue when we die?

Possibly because blood gets darker as it congeals? But what about cyanosis? This does mean surely that when blood starts to lose oxygen it appears bluer through the skin. So deoxygenated blood must have less red colouration?

[lenaroseduchannes]

So why do our lips turn blue when we die?

When we die the red blood in our bodies drains down and settles into the back of our head kinda... without the bright red blood a tiny bit of red and the skin make the lips appear blue..

[michimichi]

blue blood is just a representation for differentiate oxygenated from deoxygenated blood,blue blood is not literally blue..

[justuser]

The bood plasma relacement "Перфторан" developed in USSR has blue color.

http://ru.wikipedia.org/wiki/%D0%9F%D0% ... 0%B0%D0%BD

http://www.medline.ru/public/art/tom5/art8-perf1.phtml

http://vivovoco.rsl.ru/VV/JOURNAL/VRAN/PF/PERFTOR.HTM

The term "blue blood" was widely used in russian media as synonymous of the blood plasma replacement in articles about war in Afghanistan.

[ablettakbar]

Human blood is always red, however creatures like the Horseshoe crab have blue blood, this is because they do not use hemoglobin to attract oxygen (iron based) but instead use hemocyanin (copper based) it must be a more efficent way of delivering oxygen to the cells as they have survived all the great extinctions